Stripper mechanism for punching presses



March 19, 1929. J ROHLFING 1,706,075

STRIPPER MECHANISM FOR PUNCHING PRESSES Filed y 1928 2 Sheets-Sheet l March 19, 1929. bHLF 1,706,075

STRIPPER MECHANISM FOR PUNCHING PRESSES Filed May 1928 2 Sheets-Sheet 2 Patented Mar. 19, 1829.

UNITED STAT PATENT @FFEQE.

ASSIGI'IOB. T AMERICAN CAR AND FOUNDRY COMPANY, 0F NEW YORK, N. 5., A CQRPQB-ATIGE 03 NEW STRIPPER MECHANISM F013. PUHGHING- Application filed May 1,

This invention relates to punching presses and has as an object the providing of an improved strippermechanism in which the stripper bar is positively held in engagement with the work while the punches are being withdrawn from the work and is positively raised from the work after the withdrawal of the punches.

In the drawings:

Figure 1 isa partial end elevation of a punching press equipped with a stripper mechanism constructed in accordance with this invention;

2 is an end elevation of the means for holding an end of the stripper bar in its low ermost position, other parts of the punching press being shown to show the relation of the holding means thereto;

Fig. 3 is a horizontal section of the holding meanstaken on the line 33 of Fig. 2;

Fig. 4 is an irregular vertical sectional view showing the stripper bar and guide bracket in section, the link, cam and clamping bar in side elevation, and

Fig. 5 is a vertical section taken on the line 55 of Fig. 4.

In the drawings, the invention is shown applied to a punching press having a. stationary bed 1 and a movable head 2, dies 3 being mounted on the bed 1 and punches 4 secured to the movable head 2 in the usual manner. Extending from side to side of the press is a stripper bar 6 having notches 8 adjacent each end thereof and flanges or cars 10 projecting from the bar 6 on both sides of each notch 8 on one side of the stripper bar. Mounted between the flanges 10 of each notch 8 is an extension member or arm 12 having a nose or lug l4 engaging in the notch 8, the arm 12 being held in engagement with the stripper bar 6 by bolts 16 which are inserted in alined openings in the flanges 10 and arms 12. The lugs 14 and the stripper bar 6 at the notches 8 are provided with alined openings 17-and 18 respectively, the openings 18 being of uniform diameter throughout, while the openings 17 are partly of the same diameter as the openings 18. and partly of a lesser diameter, thereby forming shoulders 19. Loosely mounted in the openings 17 and 18 are bolts 20 having heads 21 which engage with the shoulders 19 and having their threaded ends projecting through openings in the movable head 2 and secured therein by nu s 22. This construction. furnishes a. lost -the stripper bar 1928. Serial No. 274,286.

motion connection between the movable head 2 and the stripper bar 6 which pemits of engaging the work before the punches 4 do and of remaining in contact with the work until after the punches have been disengaged therefrom.

Secured to the body 1 at each side thereof is a guide bracket- 23 comprising a base 24 which rests upon the bed 1 and is provided with openings 25 which receive the securing bolts 26 and spaced parallel sides 2'? which project perpendicularly to the base 24 and are provided at their upper ends with inwardly projecting flanges 28 which with the connect ing web 30 form a guide slot for the reception of the guide flanges 32 formed on the opposite sides of each arm 12.

The lower ends of the arms 12 are bifurcated to form the jaws 34 in which are pivotally mounted the ends of clamping bars 36 which extend between the sides 27 of the guide brackets 23 and have their other ends which are rounded as at 37 movably supported on wear plates 38 inserted in openings in bases 24 of the guide brackets 23.

Mounted in openings in bosses on the sides 27 of the guide brackets 23 are pins 40 on which triangular shaped cams 42 are mounted between the sides 27. The cams 42 are provided at one corner thereof with openings in which are mounted the pins 44 which are secured in the cams by set screws 45 and project on both sides of the cams 42. The pins 44 engage in slots 46 in jaws 48 formed in the lower ends of links 50 which have their upper ends rotatablv mounted on pins 52 carried by brackets 54 secured to the movable head 2 by bolts 55.

Assuming the parts to be positioned as shown in F 4. operation of the movable head 2 to cause the punches 4 to act on the work 56 (shown in broken lines) will also lower the stripper bar 6 until it rests on the work 56 carrying with it t-he arms 12 and the bars 36 until the bars 36 are substantially in engagement with the base of the guide bracket 23. This movement of the head 2 also lowers the links 50 which at first permit the cams 42 to rotate on the pins 40 until the cams engage the bars and during the last portion of their movement. the links 50 force the cams 42 into engagementwith the bars 36 so as to secure the bars 36 in the position shown in Fig. 1. In case a cam 42 binds and does not rotate upon the first downw increment of the link 50, the guides 58 on the sides 27 of the guide bracket 23 guide the lower end of the link 50 outwardly and guide the link in forcing the cam to rotate. Then the movable head 2 is raised to withdraw the punches from the work 56, the lost motion connections between the bolt 20 and the stripper bar 6 and between the link 50 and the cam -12 permits the withdrawal of the punches l from the work 56 before the heads 21 of bolts 20 engage with the shoulders 19 and before the links 50 operate the cams 42, thus insuring the strip .3 and 'Jreventing the liftiru of the work b the binding of the punches l in the openings in the work. Further upward movement of the head 2 causes the links 50 to operate the cams 4:2- to releasethe bars 36 and causes the heads 21 of bolts 20 to engage with the shoulders 19 and to raise'the stripper bar 6 from the work 56.

' While the preferred embodiment of the in vention has been shown and described, it is to be understood that the invention is not limited to the exact details of con 'uction shown and described, as it is obvious that various modifications thereof within the scope of the claims will occur to persons skilled in the art.

What is claimed is:

1. In a punching press having a movable head, a stripper bar carried by said head, a clamping bar connected to said stripper bar and a cam operated by said head to engage said clamping bar and prevent movement of a said stripper bar.

2. In a punching press having a stationary bed and a movable head, a stripper bar carried by said head andhaving a lost motion connection therewith, a clamping bar connected to said stripper bar, a cam, and an operative connection between said cam and head having a lost motion therein, said cam engaging said clamping bar to hold said stripper bar on said bed during the taking up of the lost motion by said head.

3. In a punching press having a stationary bed and a movable head, a stripper bar carried by said head, a clamping bar pivotally connected to said stripper bar and bearing.

on said bed, and a cam operated by saidhead and engaging said clamping bar toholdsaid stripper bar to said bed.

4;. In a punching press having a stationary bed and a movable head, a stripper bar carried by said head, an arm secured to said stripper bar, a clamping bar pivotaliy connected to said arm and slidably supported on said bed, a cam pivotally mounted on said bed and operated from said head to engage said clamping device.

5. In a punching press having a stationary bed and a movable head, a stripper bar carried by said head, an arm secured to said stripper bar, a clamping bar pivotally connected to said arm and bearing onsaid bed, a cam pivotally mounted on said bed, and a link forming a lost motion "connection between said cam and head and operating said cam to engage and disengage said clamping bar upon movement of said head.

v 61 In a punching press having a stationary bed and a movable head, a stripper bar carried by the movable head, an arm secured to said stripper bar, a clamping bar pivotally connected to said arm and bearing on the stationary bed, and a cam operated from said movable head and engagingsaid clamping bar, to hold said stripper barfin engagement with the work.

7. In a punching'press having a stationary bed and a movable head, a stripper bar carried by said movable head, an arm secured to said stripper bar and'movable therewith, a clamping bar pivotally connected to said arm and bearing on said stationarybed, a cam rotatably mounted on said stationary bed, and a link connected to said movable head and cam and operating said cam to engage said clamping bar to holdsaid stripper bar against movement.

8. In a punching press having a stationary bed and a movable head, a stripper bar carried by said head and havinga lost motion connection therewith, an arm secured to said stripper bar, a guide bracket for said arm mounted on said bed, a clamping bar pivotally co nnected to said arm and slidably supported on said bed, a cam pivotally mounter, on said guide bracket and engaging said clamping bar when rotated, anda link carried by said head and having a lost motion connection with said cam to rotate said cam into engagement with said clamping bar.

9. In a punching press having a vertically reciprocable head, a stripper bar carried by said head, a clamping bar connected to said stripper bar anda cam operat-ively connected to said head and engaging said clamping bar to prevent movement of; said stripper bar.

In witness whereof I have hereunto set 

